herokuでのエラー

PythonでLINEの「Messaging API」でテンプレートメッセージを実装してみた
を参考にしながらLINEのBOTを作っているのですが、BOTからメッセージが返ってきません
エラーを見ると環境変数あたりでKeyErrorを起こしているようですが、よくわかりません
ただ、herokuで確認してもちゃんと設定できているみたいです...

御教授おねがいします

エラー

$ heroku logs
2019-06-11T02:50:32.472033+00:00 app[api]: Enable Logplex by user <自分のメールアドレス>
2019-06-11T02:50:32.472033+00:00 app[api]: Release v2 created by user <自分のメールアドレス>
2019-06-11T02:50:31.993986+00:00 app[api]: Release v1 created by user <自分のメールアドレス>
2019-06-11T02:53:48.627397+00:00 app[api]: Release v3 created by user <自分のメールアドレス>
2019-06-11T02:53:48.627397+00:00 app[api]: Set YOUR_CHANNEL_SECRET config vars by user <自分のメールアドレス>
2019-06-11T02:56:09.575589+00:00 app[api]: Set YOUR_CHANNEL_ACCESS_TOKEN config vars by user <自分のメールアドレス>
2019-06-11T02:56:09.575589+00:00 app[api]: Release v4 created by user <自分のメールアドレス>
2019-06-11T02:59:07.000000+00:00 app[api]: Build started by user <自分のメールアドレス>
2019-06-11T02:59:53.098332+00:00 app[api]: Deploy f38d8d89 by user <自分のメールアドレス>
2019-06-11T02:59:53.098332+00:00 app[api]: Release v5 created by user <自分のメールアドレス>
2019-06-11T02:59:53.116013+00:00 app[api]: Scaled to web@1:Free by user <自分のメールアドレス>
2019-06-11T02:59:57.335690+00:00 heroku[web.1]: Starting process with command `python app.py`
2019-06-11T03:00:00.250321+00:00 heroku[web.1]: State changed from starting to crashed
2019-06-11T03:00:00.258294+00:00 heroku[web.1]: State changed from crashed to starting
2019-06-11T03:00:00.113464+00:00 app[web.1]: Traceback (most recent call last):
2019-06-11T03:00:00.113498+00:00 app[web.1]: File "app.py", line 15, in <module>
2019-06-11T03:00:00.113691+00:00 app[web.1]: LINE_CHANNEL_ACCESS_TOKEN = os.environ["LINE_CHANNEL_ACCESS_TOKEN"]
2019-06-11T03:00:00.113698+00:00 app[web.1]: File "/app/.heroku/python/lib/python3.7/os.py", line 678, in __getitem__
2019-06-11T03:00:00.114171+00:00 app[web.1]: raise KeyError(key) from None
2019-06-11T03:00:00.114205+00:00 app[web.1]: KeyError: 'LINE_CHANNEL_ACCESS_TOKEN'
2019-06-11T03:00:00.231629+00:00 heroku[web.1]: Process exited with status 1
2019-06-11T03:00:02.000000+00:00 app[api]: Build succeeded
2019-06-11T03:00:03.594174+00:00 heroku[web.1]: Starting process with command `python app.py`
2019-06-11T03:00:05.525896+00:00 heroku[web.1]: State changed from starting to crashed
2019-06-11T03:00:05.504293+00:00 heroku[web.1]: Process exited with status 1
2019-06-11T03:00:05.417426+00:00 app[web.1]: Traceback (most recent call last):
2019-06-11T03:00:05.417461+00:00 app[web.1]: File "app.py", line 15, in <module>
2019-06-11T03:00:05.417735+00:00 app[web.1]: LINE_CHANNEL_ACCESS_TOKEN = os.environ["LINE_CHANNEL_ACCESS_TOKEN"]
2019-06-11T03:00:05.417758+00:00 app[web.1]: File "/app/.heroku/python/lib/python3.7/os.py", line 678, in __getitem__
2019-06-11T03:00:05.418340+00:00 app[web.1]: raise KeyError(key) from None
2019-06-11T03:00:05.418393+00:00 app[web.1]: KeyError: 'LINE_CHANNEL_ACCESS_TOKEN'
2019-06-11T03:17:19.519946+00:00 heroku[web.1]: State changed from crashed to starting
2019-06-11T03:17:19.329136+00:00 app[api]: Set LINE_CHANNEL_SECRET config vars by user <自分のメールアドレス>
2019-06-11T03:17:19.329136+00:00 app[api]: Release v6 created by user <自分のメールアドレス>
2019-06-11T03:17:22.897205+00:00 heroku[web.1]: Starting process with command `python app.py`
2019-06-11T03:17:25.372001+00:00 heroku[web.1]: State changed from starting to crashed
2019-06-11T03:17:25.377198+00:00 heroku[web.1]: State changed from crashed to starting
2019-06-11T03:17:25.265214+00:00 app[web.1]: Traceback (most recent call last):
2019-06-11T03:17:25.265243+00:00 app[web.1]: File "app.py", line 15, in <module>
2019-06-11T03:17:25.265543+00:00 app[web.1]: LINE_CHANNEL_ACCESS_TOKEN = os.environ["LINE_CHANNEL_ACCESS_TOKEN"]
2019-06-11T03:17:25.265586+00:00 app[web.1]: File "/app/.heroku/python/lib/python3.7/os.py", line 678, in __getitem__
2019-06-11T03:17:25.266245+00:00 app[web.1]: raise KeyError(key) from None
2019-06-11T03:17:25.266317+00:00 app[web.1]: KeyError: 'LINE_CHANNEL_ACCESS_TOKEN'
2019-06-11T03:17:25.353006+00:00 heroku[web.1]: Process exited with status 1
2019-06-11T03:17:25.847368+00:00 heroku[web.1]: Restarting
2019-06-11T03:17:24.937069+00:00 app[api]: Remove YOUR_CHANNEL_SECRET config vars by user <自分のメールアドレス>
2019-06-11T03:17:24.937069+00:00 app[api]: Release v7 created by user <自分のメールアドレス>
2019-06-11T03:17:28.330708+00:00 heroku[web.1]: Starting process with command `python app.py`
2019-06-11T03:17:29.227677+00:00 heroku[web.1]: Starting process with command `python app.py`
2019-06-11T03:17:30.120312+00:00 heroku[web.1]: Process exited with status 1
2019-06-11T03:17:30.058190+00:00 app[web.1]: Traceback (most recent call last):
2019-06-11T03:17:30.058219+00:00 app[web.1]: File "app.py", line 15, in <module>
2019-06-11T03:17:30.058356+00:00 app[web.1]: LINE_CHANNEL_ACCESS_TOKEN = os.environ["LINE_CHANNEL_ACCESS_TOKEN"]
2019-06-11T03:17:30.058359+00:00 app[web.1]: File "/app/.heroku/python/lib/python3.7/os.py", line 678, in __getitem__
2019-06-11T03:17:30.058722+00:00 app[web.1]: raise KeyError(key) from None
2019-06-11T03:17:30.058759+00:00 app[web.1]: KeyError: 'LINE_CHANNEL_ACCESS_TOKEN'
2019-06-11T03:17:31.950462+00:00 heroku[web.1]: State changed from starting to crashed
2019-06-11T03:17:31.836813+00:00 app[web.1]: Traceback (most recent call last):
2019-06-11T03:17:31.836839+00:00 app[web.1]: File "app.py", line 15, in <module>
2019-06-11T03:17:31.837198+00:00 app[web.1]: LINE_CHANNEL_ACCESS_TOKEN = os.environ["LINE_CHANNEL_ACCESS_TOKEN"]
2019-06-11T03:17:31.837204+00:00 app[web.1]: File "/app/.heroku/python/lib/python3.7/os.py", line 678, in __getitem__
2019-06-11T03:17:31.837692+00:00 app[web.1]: raise KeyError(key) from None
2019-06-11T03:17:31.837698+00:00 app[web.1]: KeyError: 'LINE_CHANNEL_ACCESS_TOKEN'
2019-06-11T03:17:31.926782+00:00 heroku[web.1]: Process exited with status 1
2019-06-11T03:17:42.406253+00:00 heroku[web.1]: State changed from crashed to starting
2019-06-11T03:17:42.213307+00:00 app[api]: Release v8 created by user <自分のメールアドレス>
2019-06-11T03:17:42.213307+00:00 app[api]: Set LINE_CHANNEL_ACCESS_TOKEN config vars by user <自分のメールアドレス>
2019-06-11T03:17:45.465540+00:00 heroku[web.1]: Starting process with command `python app.py`
2019-06-11T03:17:46.503534+00:00 app[api]: Remove YOUR_CHANNEL_ACCESS_TOKEN config vars by user <自分のメールアドレス>
2019-06-11T03:17:46.503534+00:00 app[api]: Release v9 created by user <自分のメールアドレス>
2019-06-11T03:17:46.747882+00:00 heroku[web.1]: Restarting
2019-06-11T03:17:47.571860+00:00 app[web.1]: * Serving Flask app "app" (lazy loading)
2019-06-11T03:17:47.571892+00:00 app[web.1]: * Environment: production
2019-06-11T03:17:47.571970+00:00 app[web.1]: WARNING: This is a development server. Do not use it in a production deployment.
2019-06-11T03:17:47.572011+00:00 app[web.1]: Use a production WSGI server instead.
2019-06-11T03:17:47.572037+00:00 app[web.1]: * Debug mode: off
2019-06-11T03:17:47.579300+00:00 app[web.1]: * Running on http://0.0.0.0:49935/ (Press CTRL+C to quit)
2019-06-11T03:17:49.101210+00:00 heroku[web.1]: Stopping all processes with SIGTERM
2019-06-11T03:17:49.163726+00:00 heroku[web.1]: Process exited with status 143
2019-06-11T03:17:50.968905+00:00 heroku[web.1]: Starting process with command `python app.py`
2019-06-11T03:17:53.669075+00:00 app[web.1]: * Serving Flask app "app" (lazy loading)
2019-06-11T03:17:53.669094+00:00 app[web.1]: * Environment: production
2019-06-11T03:17:53.669096+00:00 app[web.1]: WARNING: This is a development server. Do not use it in a production deployment.
2019-06-11T03:17:53.669104+00:00 app[web.1]: Use a production WSGI server instead.
2019-06-11T03:17:53.669108+00:00 app[web.1]: * Debug mode: off
2019-06-11T03:17:53.676160+00:00 app[web.1]: * Running on http://0.0.0.0:50773/ (Press CTRL+C to quit)
2019-06-11T03:17:54.880922+00:00 heroku[web.1]: State changed from starting to up